The present invention relates to a torque detector, particularly to a torque detector for detecting a torque applied to a torque transmission shaft which is connected to a load such as a wheel of an automobile.
The conventional torque detector of this type is provided with a detector shaft of which one end is connected to a driving shaft of an engine and the other end is connected to the torque transmission shaft. In this torque detector, the torque applied to the torque transmission shaft is detected by detecting the distortion occurring in the above detector shaft.
The distortion of the above shaft is detected by a detecting means of a strain gauge type comprising a strain gauge of which electric resistance varies in proportion to the distortion, of a magnetic strain type comprising a magnetic strain pipe of which magnetic property varies in accordance with the distortion or of a phase difference type, which detects a phase difference between the distortion occurring at two separated points of the detector shaft.
However, the conventional torque detector having the above structure is large in size and complex in structure. Namely, in the conventional torque detector, the torque is detected by detecting distortion occurring in the detector shaft so that if the detector shaft is short, the accuracy of the detection is low. Therefore, in order to improve the accuracy of the detection, the detector shaft must be made long.
It has been required to control the ignition timing, the air-fuel ratio and the gear ratio of the transmission of the automobile in accordance with the torque applied to the load.
However, the above described conventional torque detector is too large and too complex in structure to be mounted on the automobile practically.
Accordingly, one object of the present invention is to provide a torque detector which is small in size and simple in structure enough to be mounted on an automobile.
Another object of the present invention is to provide a torque detector for detecting the torque by detecting the angular phase difference between the driving shaft and the torque transmission shaft which is changed in response to the applied torque.
Still another object of the present invention is to provide a torque detector by which the torque can be precisely detected in the ordinary torque range and also when the torque exceeds the upper limit of the ordinary torque range, excess phase delay of the second shaft relative to the first shaft can be prevented.